1. Field of the Invention
The present invention relates to a device for deflecting a saw cable of a cable saw and including a support through which the saw cable is extendable, at least one deflection member securable to the support without a possibility of rotation relative thereto and including a receiving region connectable with the support and two support arm extending parallel to each other, and a deflection roller rotatably supported between the two support arms and having, in its outer circumferential profile, a circumferential groove a cross-section of which corresponds to a cross-section of the saw cable.
2. Description of the Prior Art
For cutting stone, concrete, steel concrete and the like constructional material, cable saw machines are used. The cable saw machine cuts the to-be-cut material by displacing a saw cable, which is provided with diamond segments. For deflecting the saw cable in different directions, at least one deflecting device is used, e.g., such as disclosed in U.S. Pat. No. 5,875,771.
U.S. Pat. No. 5,875,771 discloses a deflection device having a support and two deflection members secured to the support without a possibility of rotation relative to the support. Each deflection member includes two, extending substantially parallel to each other, support arms and a deflection roller arranged between the two arms and mounted on a rotating axle extending through the two arms. The roller has a groove which is formed in its outer circumferential profile and cross-section of which substantially corresponds to the cross-section of the saw cable. The saw cable extends from one deflection roller through the support and to another deflection roller.
During cutting with a cable saw machine, because of the variation of the cutting force and vibrations of the saw cable, the saw cable can spring off of the groove into a free space between the deflection roller and inner sides of the deflection roller-supporting support arms. If the displacement of the saw cable is not immediately noticed, i.e., the saw machine is not immediately brought to a standstill, the saw cable would cut through the parts of the saw machine itself During an operation in which the sight of separate deflection rollers is blocked from a user, e.g., during the use of a submerged cable saw, this problem cannot be eliminated even when the saw machine is operated by a very attentive user.
Accordingly, an object of the present invention is to provide a simple and economical in manufacture device for deflecting a saw cable of a cable saw machine, further a cable saw, which would insure both rapid and reliable displacement of the saw cable relative to the support without the saw cable being able to spring off of the deflection roller even when the saw cable is subjected to vibrations.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a device a deflection member of which has, in its region projecting beyond the outer profile of the deflection roller, facing each other and extending perpendicular to a rotational axis of the deflection roller, guide surfaces spaced from each other by a distance greater than the cross-section of the saw cable and corresponding at most substantially to a width of the deflection roller measured parallel to its rotational axis.
In the device according to the present invention, the two guide surfaces formed by the support arms insure that the saw cable always remains in the region of the circumferential outer profile of the deflection roller despite the tendency to spring off of the deflection roller even when the saw cable is subjected to vibrations. During the restoration of the saw cable tension and because of the specially formed outer circumferential profile of the deflection roller, the diameter of which becomes reduced toward the groove, the saw cable automatically returns into the groove. The deflection roller has, e.g., a rigid disc-shaped body. The circumferential region with the groove, however, can be formed, e.g., of an elastic material. As an elastic material, e.g., rubber can be used that is vulcanized over the metal body.
In order to insure proper guidance of the saw cable over the deflection roller, the guide surfaces, preferably, extend over from 25% to 100% of the circumference of the deflection roller.
The damage of the support arms by the saw cable is preferably prevented by forming the guide surfaces as replaceable wearable elements securable to the support arms. The advantage of forming the guide surfaces of replaceable elements consists in that the distance between the two guide surfaces can be changed by forming the replaceable elements with a different thickness. The replaceable elements can be formed alternatively of wear-resistant or slightly wearable material.
Because of alternating bending stresses to which the saw cable is subjected, rupture of the saw cable can take place. The rupture primarily results from a shock load in the region of the support members through which the saw cable extends. As a result, the saw cable becomes buckled in this area, and many meters of the saw cable become unusable. To prevent the action of shock loads on the saw cable, advantageously, a protective roller for the saw cable is rotatably arranged between the deflection roller and the receiving region of the deflection member and between the guide surfaces, with the rotational axis of the protective roller extending parallel to the rotational axis of the deflection roller.
In order to prevent the saw cable from springing off of the groove of the deflection roller upon alternating bending stresses being applied to the saw cable, advantageously, a distance between the deflection roller and the impact protective roller measured transverse to the rotational axis of the deflection roller substantially corresponds to the cross-section of the saw cable.
The centering of the protective roller with respect to the saw cable is insured by providing a circumferential indentation in the outer circumferential profile of the protective roller.
The diamond segments are formed of diamonds and a matrix material, both being sensitive to impacts. To prevent damage of the diamond segments when the saw cable vibrates and strikes the protective roller, at least a circumferential end region of the impact protective roller is formed of a resilient material. As a resilient material, e.g., rubber or a plastic material can be used.
In case when the cable saw machine operates with the use of cooling water, the working environment is very contaminated because high linear speeds (about 27 m/sec) and water cause the contamination, in particular in areas where the saw cable is deflected. The contamination of adjacent surfaces is prevented by providing a guard at least partially covering the circumference of the deflection roller. The guard has at least two damping elements for securing the guard to the support arm which extends along at least a portion of a guard length. The guard can be formed, e.g., of rubber or a plastic material. The clamping elements extend transverse to the rotational axis of the deflection roller and are pinned on both support arms. The guard can be displaced along the support arms as the departure angle of the saw cable varies between 0xc2x0 and 180xc2x0.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.